With constant growing of population and social development in the world, the resources on earth are consumed at an alarming rate, and depletion of these resources becomes an urgent crisis. With this concern in mind, shoe industry devotes a lot of investments in research and development trying to make shoe outsoles by combining plant waste and thermoplastic rubber (TPR) and hopes to avoid over consumption of petrochemical resources and achieve energy saving and reduce carbon footprint, and alleviate greenhouse effect and global warming.
Plant waste generally cannot withstand high temperature due to plant characteristics. The thermoplastic rubber (TPR) process in the conventional technique mentioned above is performed at a high temperature. Hence, in the conventional manufacturing process of joining the plant waste and thermoplastic rubber (TPR) for making shoe outsoles, the plant waste is darkened at the high temperature. This not only makes the appearance not attractive, the finished products also have unstable physical properties and shorter lifetime.
How to develop a technique to form a stronger joining between the hydrophilic plant waste and the lipophilic thermoplastic rubber (TPR) to overcome the shortcomings of the conventional techniques is an important issue in the shoe industry. The present invention aims to provide an eco-friendly approach to comply with the 4R principles: Reduce, Reuse, Recycle and Renewable.